This section provides background information related to the present disclosure, which is not necessarily prior art.
Exhaust gas can be ionized with a suitable exhaust ionizer, such as a corona discharge device or plasma reactor, to facilitate collection of particulate matter, such as with a charged particle collection device charged opposite to exhaust charged by the ionizer. Exhaust ionizers facilitate collection of particulate matter, but can undesirably increase the presence of undesirable constituents in the exhaust, such as NOx. Regulations governing vehicle emissions are primarily concerned with the following: unburned hydrocarbons (HC), carbon monoxide (CO), nitrogen oxides (NOx), and particulates. Particulate matter is a component of engine exhaust, such as gasoline or diesel exhaust, for example, that includes soot particles, which are primarily unburned hydrocarbons.
To reduce the undesirable constituents to an environmentally safe form, exhaust systems can include a selective catalytic converter. For example, a selective catalytic converter including an ammonia catalyst can reduce NOx to N2 and water. However, if the temperature of the catalyst is below its lightoff temperature, the selective catalytic converter will be ineffective to treat or reduce the constituent(s) it is designed to target. An improved method or system for reducing undesirable constituents and restricting their release into the environment would therefore be desirable.